This depends on whether or not you have worn a kimono before. It would be acceptable to wear a kimono in Tokyo, but you might not feel at ease in it, as the previous answer states. There’s a lot of fabric to a kimono, which is why they wear the belt around their waists!
You certainly cannot wear your kimono open (IE exposing skin) since it is a formal style of dress that is often considered to be a traditional Japanese style of dressing.
If you want to wear a kimono on the streets of Tokyo, just be ready to have lots of fabric draped around you, and a lot of bulk in the sleeves. People may stare since the kimono is not often worn by foreigners with bright patterns and colors - which is what is often considered formal for women.
IN the open is the key phrase, for wearing it open is a definite No-no. A kimono is a traditional Japanese wrap-around that has changed in cut very little for hundreds of years. It is formal dress, associated with politeness and good manners, so if you were intending to wear it to a bash or knees-up, think again. With its long sleeves and elaborate method of dressing in it, you're unlikely to feel particularly at ease, although you may well feel special.
You can see the most beautiful examples in museums such as London's Victoria and Albert museum. Even today, a silk kimono can set you back well over $1000. There are summer and winter kimonos, both of which differ greatly from a silky wrap-around you may have thought similar to a kimono.